communication engineering II for electronics Frequency analysis of discrete-time signals is usually and most conveniently performed on a digital signal processor, which may be a general-purpose digital computer or specially designed digital hardware. To perform frequency analysis on a discrete-time signal x[n], we convert the time-domain sequence to an equivalent frequency

1. ECE462 ECE442
Communication
Systems II
Spring 2022
Dr. Essam Sourour
esourour@msa.edu.eg
Lecture 1: Introduction

2. 2
Course instruction
• Instructor: Dr. Essam Sourour (esourour@msa.edu.eg)
• Assistant: Eng. Ahmed Hatem
• Lectures A: Tuesday 12:00 to 2:00 (class D116)
• Lectures B: Monday 8:00 to 10:00 (class D114)
• Lectures C: Monday 11:00 to 1:00 (class D113)
• Tutorials A: Tuesday 11:00 to 12:00 (class D116)
• Tutorials B: Sunday 9:00 to 10:00 (class E315)
• Tutorials C: Sunday 10:00 to 11:00 (class D113)
• Office hours: Saturday 11 AM to 2 PM. Also Sunday, Monday and Tuesday
mostly available (send me email)

3. 3
About the instructor
• Dr. Essam Sourour
➢ B.Sc. from Alexandria University, Alexandria, Egypt, in 1982
➢ M.Sc. from Alexandria University, Alexandria, Egypt, in 1986
➢ Ph.D. from Southern Methodist University, Dallas, Texas, 1990
• Teaching assistant in in the EE Department, Alexandria University
after graduation in 1982
• I was an Assistant, Associate and Full Professor in the EE Department,
Alexandria University
• Have industry experience with many companies in Egypt and outside
• Main interest: Mobile and Wireless communications

4. 4
Grading distribution
• Tutorial activities and assignments: 15 points
• Four quizzes: 15 points (based on best 3)
• Project: 5 points
• Report: 5 points
• E-portfolio: 2 bonus points
• Midterm exam: 20 points
• Final: 40 points
• Important university regulation: Absence from lectures and/or tutorials shall
not exceed 25%. Students who exceed the 25% limit shall not be allowed to
take the final examination.

5. 5
Course topics
• Pass Band Transmission Signal Space
• Inter-Symbol Interference (ISI)
• Noise Analysis in Continuous Modulation Schemes
• Channel Model, Max Likelihood Decoding-Probability of Error
• ASK Signal Space, Probability of Error/Generation and Detection
• PSK Signal Space, Probability of Error/Generation and Detection
• FSK Signal Space, Probability of Error/Generation and Detection
• MSK Phase tree and Trellis, GPSK Generation and Detection
• M-ary Systems, Combined Amp, and Phase, Prob. Error
• Spread spectrum, direct sequence, Frequency Hopping

6. 6
Learning outcomes
After completing this course, students will be able to
• LO1: Compare various communication systems
• LO2: Comprehend system performance in noisy and inter-symbol
interference environment
• LO3: Evaluate Communication systems performance
• LO4: Apply the ASK, PSK and FSK signal space

7. 7
Course material
• Power point presentation for each lecture
• Tutorial material and solutions
• Textbooks:
➢ B. P. Lathi and Zhi Ding, “Modern Digital and Analog Communication Systems,” Oxford university
press, 5th ed., 2019
➢ Simon Hykin and Michael Moher, “Introduction to Analog and Digital Communications,” 2nd Edition,
John Wiley, 2007.
• Supplementary Readings:
➢ J. Proakis and M. Salehi, Digital Communications, 5th Edition, McGraw Hill, 2008

8. 8
General Structure of a Digital Communication System
• Main block in a digital communication system
Formatter
Source
encoder
Channel
encoder
Modulator
Convert
to Original
Source
decoder
Channel
decoder
Demodulator
Transmitter
Receiver
SOURCE
Info.
Transmitter
Transmitted
signal
Received
signal
Receiver
Received
info.
Noise
Channel
Source User
bits bits bits
Original
source
symbols

9. 9
Main Blocks
• Formatter converts text, voice, video, or any analog signal into bits using:
➢ Character coding for text (example ASCII)
➢ Includes: Filtering, Sampling, quantization, PCM
➢ If source data is already bits, Formatter is not needed
• Source Coding reduces the bit rate of the input bits with little or no effect on
signal quality
• Channel Coding adds extra bits that are used for correcting bit errors when
the signal is received with some bit errors
• Modulation converts the bits into symbols. Each symbol carries 1 or more
bits. Symbols are transmitted from transmitter to receiver
• The opposite of the above blocks is done at the receiver

10. 10
Scope of the course
• Learning fundamental issues in designing a digital communication
system
• Techniques
➢ Formatting and source coding
➢ Modulation (Baseband and bandpass signaling)
➢ Spread Spectrum
• Performance
• Trade-off between various parameters

11. 11
Today’s Digital Communication Systems
• Mobile Communication systems: from 2G to 5G and beyond
• WLAN (Wi-Fi) all versions
• Bluetooth
• Digital Video Broadcasting (Satellite TV)
• Ethernet and computer networks
• Digital Subscriber Line (DSL)
• Fiber Optic systems
• Many others

12. 12
Features of Digital Communication System
• The source information (voice, audio, video, text, etc.) is digitized and
converted to binary (if it is not already)
• The transmitter sends a signal from a finite set of possible symbols
during a limited time
• The channel distorts, attenuates the transmitted signal and adds noise
to it.
• The receiver decides which symbol was transmitted given the noisy
received signal
• The probability of an erroneous decision is an important measure for
the system performance

13. 13
Digital versus analog communication
• Advantages of digital over analog communications:
➢ Regenerator receiver (relay station)
➢ Different kinds of digital signal are treated identically
Propagation distance
Original pulse Regenerated
pulse
Data Voice
Multimedia
A bit is a bit!
Text

14. 14
Why Digital is Better than Analog
• Security and privacy
• Error correction capability
• Repeater capability
• Spectral efficiency
• Simpler or low-price electronic circuits
• Easier storage
• Easier to multiplex many signals on the same channel
• Easier multiple access to many users
• Flexibility of data rate as needed

15. 15
Digitization of analog signals
• Digitizing analog signals allows effective storage and transmission
• Analog signal digitization is the foundation of modern digital
communication systems
• For analog-to-digital (A/D) conversion, the sampling rate must be high
enough to permit the original analog signal to be reconstructed from
the samples by a digital-to-analog (D/A) converter
• The sampling theorem plays a huge role in signal processing,
communication theory, and A/D converter design

16. 16
What we will learn
• Pulse Modulation
➢ Sampling & Quantization
• Pulse Amplitude Modulation (PAM)
➢ Bandwidth-Noise Trade-off
• Pulse Modulation
➢ Pulse Code Modulation
➢ Pulse Width Modulation
➢ Pulse Position Modulation
• Baseband Pulse Transmission
➢ Matched Filter and Intersymbol Interference
➢ Nyquist Criterion and Adaptive Equalization
➢ Channel Modeling and Maximum Likelihood Criterion
• Passband Digital Transmission
• Spread Spectrum and Frequency Hopping

17. Faculty of
Engineering

18. 18
Any Question?